One or more integrated circuits (“IC”) dice may be assembled into an IC package by physically and electrically coupling them to a substrate made of organic or ceramic material. One or more IC packages may be physically and electrically coupled to a printed circuit board (“PCB”) to form an “electronic assembly”. The “electronic assembly” may be part of an “electronic system”. An “electronic system” is broadly defined herein as any product comprising an “electronic assembly”. Examples of electronic systems include computers (e.g., server, router, desktop, laptop, hand-held, Web appliance, etc.), wireless communications devices (e.g., cellular phone, cordless phone, pager, etc.), computer-related peripherals (e.g., printer, scanner, monitor, etc.), entertainment devices (e.g., television, radio, stereo, tape and compact disc players, video cassette recorder, camcorder, digital camera, MP3 (Motion Picture Experts Group, Audio Layer 3) player, etc.), and the like.
An IC package may comprise one or more IC dice. At least one surface of a die may comprise a number of pads or contacts to couple the die functionally to another element, such as an IC substrate. An underfill material may be used to surround those contacts in order to improve long-term reliability by mechanically coupling the IC die to the substrate and by sealing the IC die against contaminants.
An IC substrate may have a relatively large number of input/output (“I/O”) terminals (also called “lands”), as well as a large number of power and ground terminals or lands, on a surface of the IC substrate.
In the field of electronics there is competitive pressure among manufacturers to drive the performance of their equipment up while driving down production costs and maintaining acceptable yield and reliability. This is particularly true regarding the packaging of dice on substrates, where each new generation of packaging must provide increased performance, particularly in terms of higher clock frequencies, while generally being smaller or more compact in size.
In an IC package that comprises two or more IC dice, there is a likelihood that one or more voids may form within underfill material that is applied between the dice and the IC substrate. A void within the underfill material may adversely affect the long-term reliability of the IC package by weakening the mechanical bond between one or more of the IC dice and the substrate, and/or by allowing contaminants to damage the connections between the dice and the substrate.